Insulating mounting for anode grids



Oct. 4, 1932. M SCHENKEL 1,880,499

INSULATING MOUNTING FOR ANODE GRIDS Filed Aug. 26, 1951 WITNESSES:INVENTOR id Morz'fz Sake/1K6].

ATTORN EY surface.

Patented Oct. 4, 1932 UNITED STATES PATENT QFFICE MORITZ SCHENKEL, OFBERLIN-CHARLOTTENBURG, GERMANY, ASSIGNOR TO WEST- INGI-IOUSE ELECTRIC &M'ANUFAGTURING COMIANY, A COBRORATION OF PENN- SYLVANIA INSULATINGMOUNTING FOR ANODE GRIDS Application filed August 26, 1931, Serial No.559,446, and in Germany August 29, 1930.

My invention relates to an insulating mounting for an anode grid andparticularly for .such grids as used in mercury arc rectifiers.

In the construction of mercury arc rectifiers, it has been customary tosurround the anodes with a potential shield and to further protect theanode with a conducting grid. For purposes of convenience, this grid isusually mounted inside of the shield and suspended from the shield bysuitable supports, such as bolts or rivets.

To secure the best electrical performance, the grids are insulated fromthe shields in which they are mounted. However, prior to my invention,considerable difiiculty has been experienced in maintaining theinsulation between the grids and the supporting shields.

This difliculty arose from the deposition of conducting material on thegrids and their supporting mountings. This conducting materialeventually bridging any insulator used and electrically connecting thegrids and their supporting shields. The deposited conducting material ismainly material blasted off or sputtered from the anode head and carriedfrom the anode by the rectifying arc.

I have discovered that this sputtered material moves in substantially astraight line or rather an oscillatory path in the arc stream. Since thesputtered material moves in substantially a straight line, it ispossible to shield any object interposed in the arc stream byinterposing a shield on each side of the object to be protected. Theseshields will receive the sputtered material and protect the shieldedobject in substantially the same man ner as an opaque shield interceptslight.

According to my invention, the insulating 'mounting for the grid is sopositioned with respect to the arc stream that some portion of thesupporting shield is interposed between the sputtered material and theinsulating This is most conveniently accomplished by securing theinsulators in housings on the exterior of the shields and extending thegrid supports in spaced relation with openings in the shield wall andhaving the supports received in suitable recesses in the insulator.

Other objects and advantages of my invention will be apparent from thefollowing detailed description taken in conjunction with theaccompanying drawing, in which F igur 1 is a fragmentary sectionalelevation of an anode shield embodying my invention,

Fig. 2 is a modification, and

Fig. 3 is a further modification.

The apparatus disclosed in the drawing comprises an. anode stem 1, anactive head 2 and a suitable insulator 3 from which is suspended asubstantially cylindrical shield 4, preferably of sheet material.Adjacent to the anode head 2 is an anode grid 5, preferably ofconducting material, which is attached to the shield by a plurality ofrodlike supports, such as the bolts 6.

The supporting bolts 6 extend through openings 8 of greater diameterthan the supports. The ends of the supports 6 are received by suitableinsulators 10 mounted in a conducting housing 12 on the exterior of theshield. The junction between the sup porting members and the insulatingsurface being spaced from the opening in the shield wall. The spacingshould be sufficient that any material travelling from the anode headthrough the opening 8 surrounding the support should not intercept theinsulating surface adjacent to the junction 13 with the supportingmember. In this manner, the shield 4,.or portions thereof, cause shadowson the insulating surface and prevent bridging from deposition ofsputtered material.

The modification disclosed in Fig. 2 diifers from the disclosure of Fig.1 only in that the supporting members 6 have been provided withdown-turned extensions 15 so that the insulators may be used in directcompression instead of having to support the Weight of the grid inshear.

In the modification shown in Fig. 3, the housings 12 are substantiallytubular projections extending outwardly from the surface of the shieldand substantially concentric with the passage 8 for the grid support 6.The tubular housing is supplied with an insulator 16 in the form of abushing closing the open end thereof. Preferably, the supporting members6 are extended completely through the insulating bushing.

The use of a bushing in a partially open housing is particularlyadvantageous if it is desired to make electrical contact to thesupporting grid. Also, the supports extending completely through theinsulating bushings facilitate the installation and positioning of thegrids with respect to the shield.

WVhile I have shown and described a specific embodiment of my invention,it is apparent that various changes and modifications can be madetherein without departing from the spirit and scope of my invention. Idesire, therefore, that only such limitations shall be imposed as areembodied in the accompanying claims or as may be necessitated by theprior art.

I claim as my: invention 1. In a vapor electric device, an anode shield,a plurality of substantially tubular projections on the exterior of theshield, the shield having openings communicating with theinterior of theprojections, a grid in said shield, supporting members for said gridextending through said openings into said projections and insulators insaid projection for receiving the ends of the supporting members.

2. A mercury arc rectifier, an anode, an anode shield associatedtherewith, a grid in said shield, said shield having a plurality ofopenings therein, insulators mounted ad jacent said openings andsupports for said grid extending through said openings and being carriedby said insulators.

3.'In a vapor electric device, an anode, a shield around the anode, aconducting grid in said shield, said shield having a plurality ofopenings therein, casings attached to the exterior of the shield andsurrounding the openings, supporting members for said grids extendingthrough the openings into the casings and insulating members in thecasings for receiving the supporting members.

4. In a vapor electric device, an anode, a shield around the anode, aplurality of insulators mounted on the exterior of the shield,supporting members secured to said insulators and extending into theshield and a grid member supported by said members.

'5. In a mercury-arc rectifier, an anode, an anode shield, a housing onthe exterior of the shield, said shield having an opening'com-,municating with the housing, a grid in the MORITZ SCHENKEL.

